Same here. Assemble clutch disc and pressure plate to flywheel, then bellhousing, , throwout bearing, then transmission.

Leave the transmission in 4rth gear so you can turn the output shaft during install. It will turn the input shaft if the splines are not aligned.

As for alignment tools. These guys like a spare input shaft because they are the proper size but even the proper size will fit loose in a properly clearanced pilot bushing.
So even with the proper input shaft gravity will pull it down 1/4 to 1/2". Let if fall, then raise it up. Half way between those two points is where you want it while you tighten the pressure plate bolts. With that knowledge, even a deep socket or a broom stick will perfectly center it everytime.